package day07;

import java.util.Locale;
import java.util.Random;
import java.util.Scanner;

/**
 * 验证码:
 *      需求: 生成?位验证码(大写,小写,数字)
 */
public class VerificationCode {
    public static void main(String[] args) {
        String code = generateVeriCode(4);
        System.out.println("验证码:"+code);
        code = code.toLowerCase();
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入验证码:");
        String sc = scanner.next();
        sc = sc.toLowerCase();
        if (code.equals(sc)){
            System.out.println("验证成功!");
        }
    }



    public static String generateVeriCode(int len){
        String code = "";
        char[] chs = {
                'a','b','c','d','e','f','g','h','i','j','k','l',
                'm','n','o','p','q','r','s','t','u','v','w','x',
                'y','z','A','B','C','D','E','F','G','H','I','J',
                'K','L','M','N','O','P','Q','R','S','T','U','V',
                'W','X','Y','Z','0','1','2','3','4','5','6','7',
                '8','9'};
        Random rand = new Random();
        for (int i = 0; i < len; i++) { //循环len次
            int index = rand.nextInt(chs.length);//随机下标
            code += chs[index];//将随机获取的字符拼接到code
        }
        /*
            i=1     index=0     code="a"
            i=2     index=24    code="x"
            i=3     index=52    code="Z"
            i=4     index=58    code="5"
         */
        return code;
    }
}
